/*
 * The Minimal snprintf() implementation
 *
 * Copyright (c) 2013,2014 Michal Ludvig <michal@logix.cz>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *     * Redistributions of source code must retain the above copyright
 *       notice, this list of conditions and the following disclaimer.
 *     * Redistributions in binary form must reproduce the above copyright
 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
 *     * Neither the name of the auhor nor the names of its contributors
 *       may be used to endorse or promote products derived from this software
 *       without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * ----
 *
 * This is a minimal snprintf() implementation optimised
 * for embedded systems with a very limited program memory.
 * mini_snprintf() doesn't support _all_ the formatting
 * the glibc does but on the other hand is a lot smaller.
 * Here are some numbers from my STM32 project (.bin file size):
 *      no snprintf():      10768 bytes
 *      mini snprintf():    11420 bytes     (+  652 bytes)
 *      glibc snprintf():   34860 bytes     (+24092 bytes)
 * Wasting nearly 24kB of memory just for snprintf() on
 * a chip with 32kB flash is crazy. Use mini_snprintf() instead.
 *
 */

#include "mini_printf.h"

struct mini_buff {
    char *buffer, *pbuffer;
    unsigned int buffer_len;
};

static int _puts(char *s, int len, void *buf)
{
    if(!buf) {
        return len;
    }
    struct mini_buff *b = buf;
    char *p0 = b->buffer;
    int i = 0;
    /* Copy to buffer */
    for(i = 0; i < len; i++) {
        if(b->pbuffer == b->buffer + b->buffer_len - 1) {
            break;
        }
        *(b->pbuffer ++) = s[i];
    }
    *(b->pbuffer) = 0;
    return b->pbuffer - p0;
}

static int mini_strlen(const char *s)
{
    int len = 0;
    while('\0' != s[len]) {
        len++;
    }
    return len;
}

static int mini_itoa(long value, unsigned int radix, int uppercase, int unsig,
                     char *buffer)
{
    char *pbuffer = buffer;
    int	negative = 0;
    int	i = 0, len = 0;
    /* No support for unusual radixes. */
    if(radix > 16) {
        return 0;
    }
    if(value < 0 && !unsig) {
        negative = 1;
        value = -value;
    }
    /* This builds the string back to front ... */
    do {
        int digit = value % radix;
        *(pbuffer++) = (digit < 10 ? '0' + digit : (uppercase ? 'A' : 'a') + digit - 10);
        value /= radix;
    }
    while(value > 0);
    if(negative) {
        *(pbuffer++) = '-';
    }
    *(pbuffer) = '\0';
    /* ... now we reverse it (could do it recursively but will
     * conserve the stack space) */
    len = (pbuffer - buffer);
    for(i = 0; i < len / 2; i++) {
        char j = buffer[i];
        buffer[i] = buffer[len - i - 1];
        buffer[len - i - 1] = j;
    }
    return len;
}

static int mini_pad(char *ptr, int len, char pad_char, int pad_to, char *buffer)
{
    int i = 0;
    int overflow = 0;
    char *pbuffer = buffer;
    if( 0 == pad_to) {
        pad_to = len;
    }
    if(len > 10) {
        overflow = 1;
        len = 10;
        pad_to = 10;
    }
    else if(len > pad_to) {
        pad_to = len;
    }
    for(i = pad_to - len; i > 0; i --) {
        *(pbuffer++) = pad_char;
    }
    for(i = len; i > 0; i --) {
        *(pbuffer++) = *(ptr++);
    }
    len = pbuffer - buffer;
    if(overflow) {
        for(i = 0; i < 3 && pbuffer > buffer; i ++) {
            *(pbuffer-- - 1) = '*';
        }
    }
    return len;
}

int mini_vpprintf(int (*puts)(char *s, int len, void *buf), void *buf, const char *fmt, va_list va)
{
    char bf[24] = {0}, bf2[24] = {0};
    char ch = 0;
    int n = 0, len = 0;
    if(puts == (void *)0) {
        /* run puts in counting mode. */
        puts = _puts;
        buf = (void *)0;
    }
    while((ch = *(fmt++))) {
        if('%' != ch) {
            len = 1;
            len = puts(&ch, len, buf);
        }
        else {
            char pad_char = ' '; 
            int pad_to = 0;
            char l = 0;
            char *ptr = (char *)0;
            ch = *(fmt++);
            /* Zero padding requested */
            if('0' == ch) {
                pad_char = '0';
            }
            while(ch >= '0' && ch <= '9') {
                pad_to = pad_to * 10 + (ch - '0');
                ch = *(fmt++);
            }
            if(pad_to > (signed int) sizeof(bf)) {
                pad_to = sizeof(bf);
            }
            if('l' == ch) {
                l = 1;
                ch = *(fmt++);
            }
            switch(ch) {
            case 0:
                return n;
            case 'u':
            case 'd':
                if(l) {
                    len = mini_itoa(va_arg(va, unsigned long), 10, 0, (ch == 'u'), bf2);
                }
                else {
                    if(ch == 'u') {
                        len = mini_itoa((unsigned long) va_arg(va, unsigned int), 10, 0, 1, bf2);
                    }
                    else {
                        len = mini_itoa((long) va_arg(va, int), 10, 0, 0, bf2);
                    }
                }
                len = mini_pad(bf2, len, pad_char, pad_to, bf);
                len = puts(bf, len, buf);
                break;
            case 'x':
            case 'X':
                if(l) {
                    len = mini_itoa(va_arg(va, unsigned long), 16, (ch == 'X'), 1, bf2);
                }
                else {
                    len = mini_itoa((unsigned long) va_arg(va, unsigned int), 16, (ch == 'X'), 1, bf2);
                }
                len = mini_pad(bf2, len, pad_char, pad_to, bf);
                len = puts(bf, len, buf);
                break;
            case 'c' :
                ch = (char)(va_arg(va, int));
                len = mini_pad(&ch, 1, pad_char, pad_to, bf);
                len = puts(bf, len, buf);
                break;
            case 's' :
                ptr = va_arg(va, char *);
                len = mini_strlen(ptr);
                if(pad_to > 0) {
                    len = mini_pad(ptr, len, pad_char, pad_to, bf);
                    len = puts(bf, len, buf);
                }
                else {
                    len = puts(ptr, len, buf);
                }
                break;
            default:
                len = 1;
                len = puts(&ch, len, buf);
                break;
            }
        }
        n = n + len;
    }
    return n;
}

int mini_vsnprintf(char *buffer, unsigned int buffer_len, const char *fmt, va_list va)
{
    struct mini_buff b = {0};
    b.buffer = buffer;
    b.pbuffer = buffer;
    b.buffer_len = buffer_len;
    if(0 == buffer_len) {
        buffer = (void *) 0;
    }
    int n = mini_vpprintf(_puts, (buffer != (void *)0) ? &b : (void *)0, fmt, va);
    if((void *)0 == buffer) {
        return n;
    }
    return b.pbuffer - b.buffer;
}

int mini_snprintf(char *buffer, unsigned int buffer_len, const char *fmt, ...)
{
    va_list va;
    va_start(va, fmt);
    int ret = mini_vsnprintf(buffer, buffer_len, fmt, va);
    va_end(va);
    return ret;
}



